51. Vertical shaft does not extend upto the surface called
52. The hydraulic sand stowing the goaf is adopted and the face is along the strike it should be slightly oriented at to provide drainage of water.
53. During extraction of coal the minimum thickness of rib left against the goaf is
54. The value of threshold convergence in longwall mining is mm/m.
55. With a good sand stone roof the area explored may not be more than . . . . . . . . m2 at one stook extraction.
56. Mud bucket not necessary when supply of flushing water
57. First indication of roof weighting for regular fracturing roof in goaf.
58. The size of bricks generally construction of brick well are
59. Velocity of slurvy instowing has to be kep at a minimum of . . . . . . . .
60. For rotory drilling the drill rods are . . . . . . . . section
Read More Section(Coal Mining)
Each Section contains maximum 100 MCQs question on Coal Mining. To get more questions visit other sections.